Preparation of aryl thioglycollic acids



xanthate oil obtained by'diazotizing Z-amino out substituting an equal volume of 50% ethyl Patented Jan. 22, 1935 a UNITED STATES PATENT osslcs PREPARATION OF ARYL THIOGLYCOLLIC 7 V ACIDS "Herbert August Lubs and Arthur Lawrence Fox, Wilmington, Del., and Robert Archie Smith, 1 Pennsgrove, N. J., assignors to E. I; du Pont. de

Nemours & Company, Wilmington, DeL, a, corporation of Delaware I ma Drawing. Application February 27,1931;

1 Serial No. 518,886

23 Claims. (c1. 2605103) This invention relates to the preparation of the S-chlorotoluene and reacting the resultant prodorganic chernical compounds represented by the uct with potassium-ethyl xanthate, was mixed general-formula i with 500 parts of 65% ethyl alcohol and 60 parts 7 b I i of ohloro-aceticacid; '-The'resultant mixture was I g I heated with stirring to 65-7020. and 2O0 parts of -5 7 40% sodium hydroxide solution was added rapidly. The reaction was very vigorous but could be controlled by the rate of addition of the sodium hydroxide. When the addition-was completethe resultant reaction mass was stirred for about 10 10 minutes, treated with 500 parts of water and the alcohol distilled 01f. After the removal of the alcohol the solution was extracted twice with I R S C OR' 100 part portions of toluene and then boiled with v 7 bone black, filtered and cooled. The filtrate '15 wherein R represents a substituted or unsubwas a u y. acidified a t stituted. aryl nucleus and R represents an alkyl e r gh a fi f d group. These starting compounds hereinafter A v y diaslra'ble Yleld of a Product Q j called;"xanthate oils are sometimes referred (381161111 PuntY-Was P m to as-Xanthic ester oi1s H The reaction takmg place is probably llus- 20 It is known inthe art that xanthate oils can tmted by the following equatlon: a be produced by diazotizing the corresponding pri- CH3 i 7 mary aromatic amine (R,NH2) and reacting the 1 resultant with an alkali-metal-alkyl-xanthate. S-OO-G2 5+ T-C Q T It is with the conversion of the resulting g a I xanthate oils to thio-glycollic acids that this 014 invention deals specifically. This invention is the result of work carried out in an endeavor to develop a satisfactory process for the production. of. aryl thio-glycollic acids from the corresponding aryl-alkyl-xan- 0 thates (xanthate oils).- Otherobjects' were the production of thio-glycollic acids of improved Y v quality and greater yields, and in general an adm g I vancement of the art. Other objects will appear Another run similar to le I w earned 35 h i m out substituting an equal volume. of 95% ethyl These objects are realized by treating a mixalcohol for the 65% ethy co D Q Y se ture of a Xanthate oil, a halo-acetic'acid, and High yields of p excellent q y an organicsolvent orsolvents with a hydrolyzing Were. Obtained in this case also; H

agent. The organic solvent dissolves the 1 xanthate oil and facilitates its decomposition to l HI 1 1 the corresponding mercaptanby the action of Another run similar to Example I was carried the hydrolyzing agent. out substituting an equalvolume of 80% acetone The invention will be readily understood from for the 65% of ethyl alcohol. A product of exa consideration of the following examples in cellent purity was obtained. The yield in'Exam which the parts are given'by weight. ple I was slightlyhigher however. v

Example I p Example IV One hundred twenty-three (123) parts of the Another run similar to Example I was carried 5 H RS-| wherein R represents a substituted or unsunstituted aryl nucleus. H

More particularly it .relates to the preparation of such compounds from otherfchemical compounds having the formula v purity was obtainedi m ene-glycol-mono-ethyl-ether for the ethyl alcohol. As in the above examples a product of excellent quality was obtained. The yield was even higher than that obtained in Example 1.

Example V Another run similar to Example I was carried out except that for the 500 parts of 65% alcohol there was substituted an equal volume of a mixture oeigm pgixsm and behzene iijn ed in the proportion 4 to l-by' volume. Very'high yields of a very pure product were obtained.

Examplejy Another run similar to Example I was carried,

out in which the 500 parts of ethyl alcohol, was replaced by an equal Volume of methyl ,alcohol.

Yields considerably higherthamthpseiof lilxample. I were eeeeinee- The were; eteeeeellete.

purity.

Example KI};

Another run similar to Example I was carried out. In this run the 500 parts of ethylalcohol a at y e el. Yq wPe. z ..N:h t alcohol; A fair yield-pfia productof excellent I Emm zzl VH1 Another r1111 imilar taEzeem le was e n d t. le' mi fren' te eqe zeee 'iofe nyie ene was. rep aced bnaliiieddumea i p'tqpy alqq 1 9 n qdeetwa -q fex 'lentm tvfa the yield; ea er that mea t: tam i eear 9 .9 hund ed nieetyr m 9. 2. Bet i a h t a ate- Qletaie elle qiaz ei neiz' mine 5- ,9 ol ene ndr ectis th ast'tiith ,netees tlel rxlaantba s. m ed w th- 5. .0 ne teeteeae i a lzq ze 'aii efl.n t eiofc l mr acetic acid; The resultant ,mixture was heated with. straits. .t ..6 ..?Q a tll wiiia te Qt 9 Sodium x de .selut qa westfifde nidlm The reaction was very vigorous but touigpee'ontrolled by the rate of addition of the sodium hydroxide. When the addition was complet e the resultant reaction mass was stirred for [about 10 minutestreated with 500 parts of water and the alcohol distilled off. During the distillation excessive foaming was encountered. Atter the removal of the alcohol the solution was extracted tangen s. 1. .0. nattleqrt eneet ale nee t boiled with bone black, filtered and cooled. The filtrate was gradually acidified and the resulting 2-methyl-4-chloro-phenyl-thio-glycollic acid fillic acid, 2-methoxy-phenylth io-g1ycollic acid, 2-methoxy-4-chloro-phenyl-thio-glycollic acid, 2 naphthyl thio glycollic acid, 2 methyl 3 chloro-phenyl-thio-glycollic acid, 4-morpholinephenyl-thio-glycollic acid, 2-chloro-phenyl-thioglycollic acid, and 2,4,5-tri-chloro-phenyl-thio glycollic acid.

It has been found that in numerous instances it is desirable to'operate the process under pressures in excess of atmospheric. 53y so doing higher reactiontemperaturesare obtainable.

Ordinarily the amount of the halo-acetic acid .used is slightly in excess of that technically revguinea,jn thev reaction. Other halo-acetic acids,

for example, bromo-acetic acid, are suitable for lar compound, hpwever, as other decolorizing iala forexample, charcoal, may be used. While potassium xanthate is mentioned in the examples. .it should; be understood that other alkali "-metal xanthates, for instance sodium xanthate are suitable.

The hydroxides of the alkali metals are especia ly desi abl ashydr ly ins. agents. Y

Thr u hout th specifi ation andclaimsmhen the word alcohol is used generallyzitisintendegl to cover poly-hydroxy as well as mono hydroxy branched and straight chain alcohols.

The process set out above is of great technical value and as will be obvious is very wide-spread in its application. The results obtained are superior't'o that of any otherxmethod, now lgnown o apmicants- A maeny @Rparenfly W d l di ere t emhpdi: ments of this inventionmay, be made .without departing from the spirit and scope thereof it is to be understood that We do not limit ourselves to the specific embodiments thereof except as defi ed-min a pe dedcla m We claim: 1

1. r e processofpreparing,2;methyle-4-chlo1;o.- phenyl-thioeglyc ollic. acid which. comprises mixing ethyl alcohol and chloracetic. acidwithethyl 2=methylA;chloroephenyle-xanthate, adding 750- .diumhycirpxid mo in tb ...a ,1,ccho1end-. sz d ty n e .2. The processof preparing a compouridof the ierm le wherein Rv represents a. substituted or unsubstituted aryl nucleus not containing a substituent which preferentially reacts with a halo-acetic acid, which comprises mixing a. compound of the formula wherein R represents an alkyl group, with an alcohol-and chloracetic acid, adding-an alkali metal whereinR represents a substituted or unsubstitilted aryl nucleus not. containing a substituent which "preferentially reacts with a ha1o-acetic acid, which comprises mixing a compound of the formula wherein R" represents an alkyl group, with an organic solvent and chloracetic acid, adding an alkali metal hydroxide, removing theorganic solvent,acidifying and separating the product.

4. The process which comprises mixing a compound of the formula wherein R represents a substituted or unsubstitutedaryl nucleus not containing a substituent which preferentially reacts with a halo-acetic acid and R represents an alkyl group with an alcohol and a mono-halo acetic acid and thereafter hydrolyzing the xanthate oil in the mixture with alkali.

5, In theprocess of preparing'a' compound of theformula 5 a wherein R represents a substituted or unsubstituted. arylnucleus not containing a substituent which preferentially reacts with a halo-acetic acid, the step of mixing a compound of the for- R-S-(f-O-R wherein R represents a substituted or unsubstituted aryl nucleus, not containinga substituent which preferentially reacts with ,a halo-acetic acid, the steps of mixing a compound of the formula I n f wherein R represents an alkyl group, with an alcohol and chloracetic acid, adding an alkali meta hydroxide, andremoving the alcohol.

'7. In the process of preparing a compound of the formula wherein R represents asubstituted or unsubstituted aryl nucleus not containing a substituent which preferentially reacts with. a halo-acetic acid, the steps of mixing a compound of the forwherein R represents an alkyl group, with an alcohol and chloracetic acid, and adding an alkali metal hydroxide.

8. In the; process of preparing a com of the'formul r .L j I. 7

wherein R represents a substituted or unsubstitutedaryl nucleus not containing a substituent which preferentially reacts with a halo-acetic 1 acid, the steps ofmixing'a compound of the formula n-s-n-o-rv which preferentially reacts with a halo-acetic acid, the steps of mixing a compound of the formula Rsn 0R' wherein R represents an alkyl group, with a poly-hydroxy alcohol and chloracetic acid, an adding an. alkali metal hydroxide: .110. In the'process of preparing a compound of the formula t?" rz-s-n-JJ-on Wherein'R represents a substituted or unsubstituted aryl nucleus not containing a substituent which preferentially reacts with a halo-acetic acid, the steps of mixing a compound-of the formula I R,S("3.O-R'.

wherein R represents an .akyl group, with a branched chainalcohol and chloracetic acid, and adding an, alkali metal hydroxide. 11. In theprocess .of preparing a compound of the formula Wherein R represents an alkyl group, with an inert solvent and an alcohol and chloracetic acid, and adding an alkali metal hydroxide.

122. In the process of peparing a compound of I the formula 3 o I H R .s-n-o wherein R represents a substituted aryl nucleus not containing a substituentrwhich preferentially reacts with a halo-acetidacid, the stepssof mixing a compound of the formula R s o-R" wherein R" representsian alkylxgroup, with an alcohol and chloracetic acid, and adding an alkali-metal-hydroxide.

13; Inthe' process of preparing a compound of the formula n-sq r-t-on 11" wherein R represents an unsubstituted aryl nucleus, the stepsof mixing a compound of the formula wherein R represents an alkyl group, with an alcohol"and chloracetic acid; andiaddingan alkali metal hydroxide. a

14. In the" process of preparing" a. compound of the formula" i wherein Rv-represents an'aryl nucleus having one or more substituents belonging tothe group;con-. s'isting of alkyl; alkoxy, halogen and morpholine, the steps of mixing a compound ofthe formula wherein R represents an alkyl group, with an alcohol and chloracetic acid, and adding an alkali metalihydroxide. a}

15.- In theprocess of preparing a compound of; the. formula I R--S(:J(III)\OH wherein R represents an aryl nucleus having one or more substituents belonging to the group consisting of alkyl, alkoxy and'halogen, thesteps of mixing a compound of the" formula R-s-I J-o-R wherein R represents an alkyl group, with an alcohol and chloracetic acid, and adding an alkali metal hydroxide.

16;In the process of' preparing a compound of'the' formula I wherein R represents an aryl nucleus having one or more substituents-belonging to the group consisting of alkyl and halogen, the steps of mixing a compound of the formula R-S-(fi-O-R v v s I wherein R represents an alkyl group, with an alcohol and chloracetic acid, and adding an alkalimetal hydroxide.

17. In the process ofipreparingaco mm theformula I n w wherein Rrepresents; a substituted or-unsubsti tuted naphthylnucleus not containing a substite uent which preferentially reacts with a,halo.- acetic acid, the'steps of mixing a compound of the formula R-S-o-Q-Ri wherein R represents anialkyl group, with an alcohol and chloracetic acid, and adding an alkali metal hydroxide.

18. In the process of preparing a compound of the formula I wherein R represents. a substituted or unsubstituted phenyl nucleus not containing a='s'ubstitu'ent which preferentially reacts with a halo-acetic acid, the steps of mixing. a compound of the formula n-s-g o-n wherein R represents an alkyl group,'.with al cohol and chloracetic acid, and adding analkali metal hydroxide.

19. In the process of preparing a compoundof the formula wherein R represents a substituted or unsubstituted aryl nucleus not containing a-substituent which preferentially reacts with a vhalo'acetic acid, the steps of mixing a compound of the formula wherein'R representsan alkyl group; with water, an alcohol and chloracetic acid, and adding an alkali metal-hydroxide. I

21. The process of preparing an aryl thioglycollic acid which comprises reacting with anal kaline hydrolyzingagent upon a water insoluble aryl-alkyl-xanthate in the presence of a mono halogen acetic acid and in an organic medium which is a solventfor the aryl-alkyl-xanthate.

22. The process of preparing an" aryl thioglycollic acid which comprises reacting-with1aque ous caustic solution upon a water-insoluble arylalkyl-xanthate in the presence of a mono halogen acetic acid and in an alcoholic medium.

23. In the process of preparing an aryl thioglycollic acid by hydrolyzing an aryl-alkyl-xanthate to produce an aryl mercaptan and reacting the latter with a mono halogen acetic acid,

the improvement which comprises carrying out 

